The field of microfluidics has matured significantly over the past two decades. Compelling platforms have been produced to address problems in traditional cell biology techniques that were previously too difficult to solve. Limitations of traditional cell biology techniques have been primarily due to onerous labor requirements and limited spatial and temporal control of the cells' microenvironment. Microfluidics has provided significant efficiency gains by reducing reagent and cell requirements which, in turn, has allowed for high-throughput processing and analysis of a large array of experimental conditions. Microfluidic systems also offer significantly greater control of the cells' microenviroment, such as flow rate, extracellular matrix (ECM) properties, and soluble factor signaling (e.g., forming a chemical gradient in diffusion dominant conditions). However, for microfluidics to make further inroads into cell biology, new microfluidic assays must be cheaper, faster, and in qualitative agreement with techniques traditionally used by biologists. It can be appreciated that microfluidics has tremendous potential to contribute to the development of drug therapies to fight cancer, point-of-care diagnostics for HIV in developing countries, and numerous other applications that are critical to the health and well being of individuals worldwide.
While current microfluidic devices provide a significant improvement in the ability to study fundamental aspects of cell biology, the adoption of microfluidic devices in clinical settings has been slow due to the high level of technicality and external equipment required. For example, current microfluidic assay methods require steps such as washing, flushing, pipetting, and transferring of cells and other materials. As such, most conventional microfluidic devices typically incorporate external elements, such as tubing and syringe pumps, to provide the valving and the mixing functionality necessary to enable an entire assay to be performed within a microfluidic system. These external elements diminish the simplicity and advantages of a microfluidic platform for biological assays.
Further, as is known, the discovery of compounds of interest for therapeutic or research applications is a complex, multitiered process that requires a number of assays of increasing relevance, from biochemical screens and in-vitro live cell assays, to in-vivo animal models. Currently, many laboratories in the areas of natural products purification, microbiology, and toxicology are focused on isolating compounds with putative biological activity for the purpose of discovering new drugs or determining factors of microbial virulence and cytotoxicity. These laboratories have developed low-cost and relatively easy assays to identify compounds of interest through large-scale biochemical screens. In-vitro live-cell assays are an essential step before deciding to pursue costly in-vivo studies, as they: 1) provide more physiologically relevant insight on the biological activity of a compound; 2) are much more time-efficient then prior methodologies; and 3) reduce animal use. However, the accessibility of live-cell assays is limited because they require expensive equipment, a plethora of perishable reagents, and highly trained researchers. These costs and training requirements represent a significant barrier for researchers who are interested in performing an initial in-vitro screening assay. Hence, it is highly desirable to provide a microfluidic platform capable of performing assays, including in-vitro live-cell assays, which do not require any external equipment to operate and which can be adapted to a wide range of situations.
Therefore, it is a primary object and feature of the present invention to provide a functionalized lid for a microfluidic platform and a method for freezing, storing, shipping, and thawing cell suspensions in a manner that maintains their viability and allows their subsequent culture and study.
It is a further object and feature of the present invention to provide a functionalized lid for a microfluidic platform and a method for freezing, storing, shipping, and thawing cell suspensions which do not require any external equipment to operate and which can be adapted to a wide range of situations.
It is a still further object and feature of the present invention to provide a microfluidic platform and a method for freezing, storing, shipping, and thawing cell suspensions which are simple to implement and inexpensive to manufacture.
In accordance with the present invention, a lid is provided for a microfluidic; platform. The microfluidic platform includes a base having outer surface and a channel therethough for receiving fluid therein. The channel has input and output ports communicating with the outer surface. The lid includes a body having a first well extending therethrough. The first well includes first and second ports communicating therewith and is adapted for receiving a first substance therein. A first membrane extends over the first port of the lid. The first membrane retains the first substance in the first well and allows a second substance to diffuse therethrough. A non-porous second membrane extends over the second port. The second membrane preventing the second substance form diffusing therethrough.
The body may include first and second spaced surfaces. The first port communicates with the first surface and the second port communicates with the second surface. The first and second surfaces may be planar. The first surface lies in a first plane and the second surface lies in a second plane generally parallel to the first plane. An absorbent may be provided adjacent the second surface and a removable seal may overlap the second membrane for isolating the first substance in the first well. The lid is movable between a first position wherein the lid is spaced from the base to a second position wherein the lid is adjacent the channel such that the first substance communicates with the input of the channel.
In accordance with a further aspect of the present invention, a method is provided for handheld diagnostics and assays. The method includes the step of capturing a first substance in a cryopreservation fluid in a first well of a lid. The lid includes first and second ports communicating with the first well. The first substance is dialytically freeing from the cryopreservation fluid.
In addition, it is contemplated to provide a channel having an input and an output in a base. The lid is moved from a first position wherein the lid is spaced from the base to a second position wherein the lid is adjacent the channel such that the first substance communicates with the input of the channel. A first membrane may be provided over the first port of the lid. The first membrane retains the first substance in the first well and allowing a dialysis fluid to diffuse therethrough. A second membrane may be provided over the second port. The second membrane prevents a dialysis fluid from diffusing therethrough.
A channel having an input and an output in a base may be provided. The lid may be moved from a first position wherein the lid is spaced from the base to a second position wherein the lid is adjacent the channel such that the first substance communicates with the input of the channel. The first substance may be drawn through the channel, e.g. by positioning an absorbent in communication with the output of the channel.
In accordance with a still further aspect of the present invention, a method is provided from for handheld diagnostics and assays. The method includes the step of freezing a first substance in a cryopreservation fluid in a first well of a lid. The lid includes a first surface communicating with a first port of the first well and a second surface communicating with a second port of the first well. A porous membrane is affixed to the first surface so as to overlap the first port and a non-porous membrane is affixed to the second surface so as to overlap the second port. The first substance is dialytically freed from the cryopreservation fluid.
The method may further include the step of providing a channel having an input and an output in a base. The lid may be moved from a first position wherein the lid is spaced from the base to a second position wherein the lid is adjacent the channel such that the first substance communicates with the input of the channel. The first substance may be drawn through the channel, e.g. by positioning an absorbent in communication with the output of the channel. A seal may be removed from the non-porous membrane so as to allow the first substance to pass therethrough. Alternatively, the non-porous membrane may be pierced so as to allow the first substance to pass therethrough.
It is intended for the porous membrane to retain the first substance in the first well and to allow a dialysis fluid to diffuse therethrough. On the other hand, the non-porous membrane prevents the dialysis fluid from diffusing therethrough. The step of dialytically freeing the first substance from the cryopreservation fluid includes the step of depositing the lid in a dialysis fluid for a time period.